New York Yankees short stop Didi Gregorius undergoes Tommy John surgery and misses part of the 2019 season, the team announced on Friday.

"We are optimistic that he will return at some point in the season," said Yankees manager Aaron Boone. "I do not want to speculate about when."

But Boone has added that it is & # 39; realistic & # 39; is [Gregorius] plays with us for most of the season. "

Gregorius had an MRI on Thursday that revealed a tear. He and the Yankees still determine when an operation will be performed.

The team believes that during Game 2 of the American League Division Series, it was in Boston last Saturday when Gregorius injured his right elbow. The throw that did that came in the seventh inning of a game that New York finally won 6-2.

On the scene, Gregorius came rushing into the outside field to use an Ian Kinsler duo, who hit hard on the Green Monster at Fenway Park and out of the reach of Yankees leftfield Andrew McCutchen.

Aaron Boone said he believed that Didi Gregorius had been injured by throwing a pitch on a ball that collided with the Green Monster at Fenway Park during the ALDS. Jay Biggerstaff / USA TODAY Sports

When he picked up the ball, Gregorius threw him back to the infield, where he was cut off when Boston's second run of the game scored.

"After the game that day, he was in the trainer's room," said general manager Brian Cashman. "Based on his dialogue and the feeling he felt at the squeeze there, on that throw he was exactly where he had determined it."

Gregorius eventually played the injury and ended the series, which Boston won 3-1 and advanced to the ALCS.

"If something bothers him, he is wired in such a way that he just does not feel it, or he conceals it deliberately," said Cashman about Gregorius. "He is exactly the type he is not going to focus on, and he goes out and does what he can."

"Which [throw] was the conclusion of something that was a sleeping giant, I think, "Cashman added.

Cashman said that he had forgotten the previous partial tear through the years, but glimpses from Gregorius' cast made in Game 4 of the ALDS began to remind him. A few unusual short hops on relatively routine throws caught the attention of the GM.

"They were not-Didi-like," Cashman said. "So right away, in my mind, I thought," Oh, boy. I wonder if we have a real problem here? "

Like Boone, Cashman refused to provide a timetable for Gregorius' return, saying "best to stay general".

Boone said that Gleyber Torres could be the short stop of the Yankees to start the 2019 season. The second baseman, who this year was a rookie, spent a short time when Gregory was recovering from other relatively minor injuries he had this season.

"He is very capable of being a daily short stop," Boone said.

Torres had his own Tommy John surgery last year after hurting his non-throwing arm by sliding home while playing in the Yankees minor leagues. He returned from mid-season injury on time for spring training.